Distributed Network Application Security Policy Enforcement

ABSTRACT

A system validates the establishment and/or continuation of a connection between two applications over a network using a two-stage process: (1) a local security agent executing on the same source system as the source application validates the connection against a set of policies stored locally on the source system; and (2) a local security agent executing on the same destination system as the destination application validates the connection against a set of policies stored locally on the destination system. The connection is allowed or blocked depending on the outcome of the two-stage validation. Before the validation process, a policy enforcement engine distributes copies of a trusted public certificate to the source and destination local security agents, which extend their local copies of the certificate to enable them to enforce policies without the use of a backend system.

BACKGROUND

Applications connected by network infrastructure communicate with each other in order to share data and perform business operations. The connection between a source application and a destination application is established by the source application, which requests a connection from its Internet Protocol (IP) address to the IP address of the destination application, typically over a specific port. Typically, existing host-based network security technologies, such as personal firewalls, allow or restrict directional access specifically at the egress or ingress point of the communication on the host on which the communication is occurring. For example, the firewall running on the host on which the source application executes typically monitors the outbound connection attempt to the destination IP address, while the firewall running on the host on which the destination application executes typically monitors the inbound connection attempt from the source IP address. Each such security component operates in relative isolation from the other, and generally only has visibility into the network-related information of the other side (e.g., IP address, port, protocol), and not into the identity of the application executing on the other host.

The limited information available to each host in such a communication restricts the types of decisions that existing security technologies can make, and allows for the hosts that are party to communications to be exploited, such as by spoofing their legitimate IP addresses to make or receive unauthorized communications.

SUMMARY

A system validates the establishment and/or continuation of a connection between two applications over a network using a two-stage process: (1) a local security agent executing on the same source system as the source application validates the connection against a set of policies stored locally on the source system; and (2) a local security agent executing on the same destination system as the destination application validates the connection against a set of policies stored locally on the destination system. The connection is allowed or blocked depending on the outcome of the two-stage validation. Before the validation process, a policy enforcement engine distributes copies of a trusted public certificate to the source and destination local security agents, which extend their local copies of the certificate to enable them to enforce policies without the use of a backend system. This validation system protects against policy violations that are not detected by traditional systems, and does so without requiring alterations to the source application, the destination application, or the network traffic between them.

Other features and advantages of various aspects and embodiments of the present invention will become apparent from the following description and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a dataflow diagram of a system for performing symmetrical validation of communications between applications over a network according to one embodiment of the present invention.

FIGS. 2A-2C are flowcharts of a method for performing the symmetrical validation of FIG. 1 according to one embodiment of the present invention.

FIG. 3 is a dataflow diagram of a system for performing symmetrical validation of communications between applications over a network without using a backend system for policy enforcement according to one embodiment of the present invention.

FIGS. 4A-4C are flowcharts of a method for performing the symmetrical validation of FIG. 3 according to one embodiment of the present invention.

DETAILED DESCRIPTION

Embodiments of the present invention perform symmetrical validation of communication between applications (or services) over a network, using agents installed on the same systems as the applications (or services), and without the need for validation by a central system. Such validation enables an imposter application to be detected and prevented from communicating even if the imposter application communicates, or attempts to communicate, using the same name and communication content as a permitted application. Embodiments of the present invention achieve this result by validating applications using application fingerprints that can distinguish permitted from prohibited applications based on features other than mere application name and communication content. Additional details and embodiments of the present invention will be described in more detail below.

The term “application,” as used herein, includes both applications and services. Therefore, any reference herein to an “application” should be understood to refer to an application or a service.

Referring to FIG. 1, a dataflow diagram is shown of a system 100 for performing symmetrical validation of communication between applications over a network. Referring to FIG. 2A, a flowchart is shown of a method 200 a performed by a policy management engine 110 according to one embodiment of the present invention.

The system 100 includes a source system 102 a and a destination system 102 b. A “system,” as that term is used herein (e.g., the source system 102 a and/or destination system 102 b), may be any device and/or software operating environment that is addressable over an Internet Protocol (IP) network. For example, each of the source system 102 a and the destination system 102 b may be any type of physical or virtual computing device, such as a server computer, virtual machine, desktop computer, laptop computer, tablet computer, smartphone, or wearable computer. The source system 102 a and the destination system 102 b may have the same or different characteristics. For example, the source system 102 a may be a smartphone and the destination system 102 b may be a server computer. A system (such as the source system 102 a and/or destination system 102 b) may include one or more other systems, and/or be included within another system. As merely one example, a system may include a plurality of virtual machines, one of which may include the source system 102 a and/or destination system 102 b.

The source system 102 a and destination system 102 b are labeled as such in FIG. 1 merely to illustrate a use case in which the source system 102 a initiates communication with the destination system 102 b. In practice, the source system 102 a may initiate one communication with the destination 102 b and thereby act as the source for that communication, and the destination system 102 b may initiate another communication with the source system 102 a and thereby act as the source for that communication. As these examples illustrate, each of the source system 102 a and the destination system 102 b may engage in multiple communications with each other and with other systems, and may act as either the source or destination in those communications. Furthermore, the system 100 may include additional systems, all of which may perform any of the functions disclosed herein in connection with the source system 102 a and the destination system 102 b.

The source system 102 a includes a source application 104 a (which may, for example, be installed and executing on the source system 102 a) and the destination system 102 b includes a destination application 104 b (which may, for example, be installed and executing on the destination system 102 b). Each of these applications 104 a and 104 b may be any kind of application, as that term is used herein. The source application 104 a and the destination application 104 b may have the same or different characteristics. For example, the source application 104 a and destination application 104 b may both be the same type of application or even be instances of the same application. As another example, the source application 104 a may be a client application and the destination application 104 b may be a server application, or vice versa.

An embodiment will now be described for enforcing security policies on a communication that the source system 102 a attempts to initiate with the destination system 102 b. In this embodiment, the source system 102 a includes a local security agent 106 a and the destination system 102 b includes a local security agent 106 b. More generally, a local security agent may be contained within (e.g., installed and executing on) any system that executes one or more applications to which the security techniques disclosed herein are to be applied. A local security agent may, for example, execute within the same operating system on the same system as the application(s) that the local security agent monitors. Each such local security agent (e.g., the local security agents 106 a and 106 b) may include any combination of hardware and/or software for performing the functions disclosed herein.

The system 100 also includes a policy management engine 110. The policy management engine may include any combination of hardware and/or software for performing the functions disclosed herein. In the particular embodiment illustrated in FIG. 1, the policy management engine 110 is contained within (e.g., installed and executing on) a remote system 112. The remote system 112 may be any device and/or software application that is addressable over an IP network. For example, the remote system 112 may be any type of computing device, such as a server computer, virtual machine, desktop computer, laptop computer, tablet computer, smartphone, or wearable computer. The remote system 112 and the source and destination systems 102 a-b may have the same or different characteristics. For example, the source and destination systems 102 a-b may be smartphones and the remote system 112 may be a server computer.

Some or all of the local security agents 106 a-b may report the state of the local applications as well as the state of the network on their system to the policy management engine 110 (FIG. 2A, operation 202). For example, in FIG. 1, the local security agent 106 a is on the same system as and monitors the source application 104 a. The local security agent 106 a may, therefore, obtain state information about the source application 104 a and report some or all of that state information, and/or information derived therefrom, to the policy management engine 110. Although in the example of FIG. 1 only one source application 104 a is shown on the source system 102 a, any number of source applications may execute on the source system 102 a, and the local security agent 106 a may obtain and report state information for some or all of such source applications to the policy management engine 110. The local security agent 106 a may also report information about the network configuration on source system 102 a that will help the policy management engine 110 identify system 102 a to other systems independent of the applications that may be executing. The local security agent 106 a may also report information about the system network topology of the source system 102 a, such as its IP addresses and/or Address Resolution Protocol (ARP) cache. All such reporting is represented by communication 114 in FIG. 1. Such communication 114 may be implemented in any of a variety of ways, such as by the local security agent 106 a transmitting (e.g., via IP and/or another network communication protocol) one or more messages containing the obtained application state and network configuration information to the policy management engine 110.

Similarly, the local security agent 106 b on the destination system 102 b may obtain and transmit state information for the destination application 104 b (and for any other applications executing on the destination system 102 b) and for the network configuration information of destination system 102 b and transmit such information via communication 116 to the policy management engine 110 in any of the ways disclosed above in connection with the local security agent 106 a, the source system 102 a, the source application 104 a, and the communication 114.

The policy management engine 110 may receive the transmitted state information 114 and 116 and store some or all of it in any suitable form (FIG. 2A, operation 204). As described above, such state information may include both application state information and network topology information (e.g., addresses, listening ports, broadcast zones). The policy management engine 110 may, for example, store such state information 114 and 116 in a log (e.g., database) of state information received from one or more local security agents (e.g., local security agents 106 a-b) over time. Such a log may include, for each unit of state information received, an identifier of the system (e.g., source system 102 a or destination system 102 b) from which the state information was received. In this way, the policy management engine 110 may build and maintain a record of application state and network configuration information from various systems over time.

The policy management engine 110 may include or otherwise have access to a set of policies 118, which may be stored in the remote system 112. In general, each of the policies 118 specifies both a source application and a destination application, and indicates that the source application is authorized (or not authorized) to communicate with the destination application. A policy may specify, for the source and/or destination application, any number of additional attributes of the source and/or destination application, such as any one or more of the following, in any combination: user(s) who are executing the application (identified, e.g., by username, group membership, or other identifier), system(s), network subnet, and time(s). A policy may identify its associated source and/or destination application using an application fingerprint which may, for example, identify the application by its name and any other attribute(s) which may be used to authenticate the validity and identify of an application, such as any one or more of the following in any combination: filename, file size, cryptographic hash of contents, and digital code signing certificates associated with the application. An application fingerprint in a policy may include other information for its associated source and/or destination application, such as the IP address and port used by the application to communicate, whether or not such information is used to define the application.

The policy management engine 118 provides, to one or more systems in the system 100 (e.g., the source system 102 a and destination system 102 b), policy data, obtained and/or derived from the policies, representing some or all of the policies that are relevant to the system to which the policy data is transmitted, which may include translating applications into IP address/port combinations (FIG. 2A, operation 206). For example, the policy management engine 110 may identify a subset of the policies 118 that are relevant to the source system 102 a and transmit a communication 120 representing the identified subset of policies to the source system 102 a. The source system 114 a may receive the communication 120 and store source system policy data 124 a, representing the received policies, in the source system 102 a. Similarly, the policy management engine 110 may identify a subset of the policies 118 that are relevant to the destination system 102 b and transmit a communication 122 representing the identified subset of policies to the destination system 102 b. The destination system 114 b may receive the communication 122 and store destination system policy data 124 b, representing the received policies, in the destination system 102 b.

The policy management engine 110 may identify the subset of the policies 118 that are relevant to a particular system (e.g., the source system 102 a and/or the destination system 102 b) in any of a variety of ways. For example, the policy management engine 110 may identify a policy as relevant to a system if the policy refers to an IP address of the system or an application that is installed and/or executing on the system.

The policy management engine 110 may extract the policy data that is relevant to the systems 102 a and 102 b and transmit the resulting policy data communications 120 and 122 in response to any of a variety of triggers. For example, the policy management engine 110 may extract and transmit relevant policy data (in the form of instances of the communications 120 and 122) to the systems 102 a and 102 b:

-   -   periodically (e.g., every second, every minute, or at any         scheduled times);     -   in response to a change in the master policy data ;     -   in response to a change in network topology, e.g., an assignment         of a network address to one of the systems 102 a-b or a change         in an assignment of an existing address;     -   in response to a new application executing on one of the systems         102 a-b;     -   in response to an existing application in the system 100         changing or adding a port on which it is listening for         connections;     -   in response to an unexpected condition on systems 102 a-b or         other systems in the network.

The policy management engine 110 may only transmit updated policy data to one of the systems 102 a and 102 b if the updates are relevant to that system. Regardless of the trigger, in response to receiving the relevant policy data 120 and 122, the systems 102 a and 102 b may update their local policy data 124 a and 124 b in accordance with the received communications 120 and 122, respectively. Receiving and maintaining updated copies of relevant policy data enables local systems, such as the systems 102 a and 102 b, to apply the policies that are relevant to them without the need to communicate with a remote system or component, such as the remote system 112 or policy management engine 110.

Before describing the system 100 and methods 200 a-c in more detail, it will be useful to note that the system 100 may operate in one of at least three security modes in relation to any particular connection between two applications (e.g., the source application 104 a and the destination application 104 b):

-   -   (1) Optimistic: The connection between the two applications is         allowed unless and until the reconciliation engine 128 instructs         the agents associated with those applications to terminate the         connection due to a policy violation.     -   (2) Pessimistic: The connection between the two applications is         terminated after a specified amount of time has passed if the         reconciliation engine 128 does not affirmatively instruct the         agents associated with those applications to keep the connection         alive.     -   (3) Blocking: The connection between the two applications is         blocked unless and until the reconciliation engine 128         affirmatively instructs the agents associated with those         applications to allow the connection.

Note that the system 100 may, but need not, operate in the same security mode for all connections within the system 100. The system 100 may, for example, operate in optimistic security mode for some connections, operate in pessimistic security mode for other connections, and operate in blocking security mode for yet other connections. As yet another example, the system 100 may switch from one mode to another for any given connection or set of connections in response to detected conditions, as will be described in more detail below.

Referring now to FIG. 2B, a flowchart is shown of a method 200 b that is performed by the source local security agent 106 a in one embodiment of the present invention to process an outgoing connection request. Note that although the method 200 b of FIG. 2B may be performed following the method 200 a performed by the policy management agent 110 in FIG. 2A, this is merely an example and not a requirement of the present invention. Rather, the method 200 b of FIG. 2B (and the method 200 c of FIG. 2C) may operate independently of the method 200 a of FIG. 2A.

Now consider an example in which the source application 104 a makes a network request to communicate with the destination application 104 b. Although this particular example will be described in connection with this particular request, the techniques disclosed herein may be applied more generally to any request made by any application to communication with any other application.

The local security agent that is on the same system as the requesting application, which in this example is the local security agent 106 a that is on the same system 102 a as the requesting application 104 a, detects that the requesting application 104 a has made the communication request, intercepts the request, and blocks the request from proceeding further at least until the source local security agent 106 a has evaluated whether the request matches a local policy (FIG. 2B, operation 208). The local security agent 106 a identifies, based on the request, the application 104 a that is the source of the request (FIG. 2B, operation 210). The local security agent 106 a evaluates the request against the locally stored policies 124 a in order to determine whether to allow or deny the request based on any one or more of the following, in any combination: the identity of the source application 104 a, the IP address and port of the destination application 104 b, some or all of the contents of the request, and the local policy data 124 a (FIG. 2B, operation 212).

The local security agent 106 a determines, based on its evaluation, whether one of the local policies 124 a covers the communication request (FIG. 2B, operation 214). If one of the local policies 124 a does cover the request, then the local security agent 106 a determines whether the covering policy allows or denies the request (FIG. 2B, operation 216). If the covering policy allows the request, then the local security agent 106 a determines whether the covering policy is current (FIG. 2B, operation 218). The local security agent 106 a may determine whether the covering policy is current in any of a variety of ways. For example, in certain embodiments, the policy management engine 110 may inform the local security agent 106 a that particular policies are current or not current. The local security agent 106 a may treat any particular policy as current in response to being informed by the policy management engine 110 that the policy is current, unless and until the policy management engine 110 subsequently informs the local security agent 106 a that the policy is no longer current. As another example, the local security agent 106 a may convert the status of a policy from current to not current after some predetermined amount of time has passed from when the local security agent 106 a previously set the status of the policy to current.

If the covering policy is current, then the local security agent 106 a sets its security mode to optimistic mode (FIG. 2B, operation 226); otherwise, the local security agent 106 a sets its current security mode to pessimistic security mode (FIG. 2B, operation 224). If the covering policy allows the request, then the local security agent 106 a allows the request (FIG. 2B, operation 232), regardless of whether the local policy is current.

If, in operation 232 of FIG. 2B, the local security agent 106 a decides to allow the communication request, then, in general, the local security agent 106 a allows the communication request to be transmitted to the destination application 104 b. Such transmission may occur using traditional techniques. In other words, the local security agent 106 a may unblock the communication request and permit it to be transmitted normally.

If, in operation 214, the local security agent 106 a determines that none of the local policies 124 a covers the request, or, in operation 216, the local security agent 106 a determines that the covering policy denies the request, then the local security agent 106 a determines whether its current security mode is blocking security mode (FIG. 2B, operation 220). Furthermore, note that the local policies 124 a may include a policy which specifically indicates the action to be performed if none of the local policies 124 a covers the request. If the local policies 124 a include such a policy, then the local security agent 106 a may perform the action specified by that policy if the local security agent 106 a determines that none of the local policies 124 a covers the request.

If the local security agent 106 a's current security mode is blocking security mode, then the local security agent 106 a transmits the request to the policy management engine 110 and awaits a response from the policy management engine 110 (FIG. 2B, operation 222). The policy management engine 110 then evaluates the request against the central policies 118 and sends a response to the local security agent 106 a indicating whether the request should be allowed or denied, based on the central policies 118. The local security agent 106 a receives the response 120 from the policy management engine 110 and determines whether the response 120 indicates that the request should be allowed or denied (FIG. 2B, operation 230). If the response 120 from the policy management engine 110 indicates that the request 130 should be allowed, then the local security agent 106 a allows the connection request (FIG. 2B, operation 232); otherwise, the local security agent 106 a denies the connection request (FIG. 2B, operation 228). The local security agent 106 a also denies the connection request (FIG. 2B, operation 228) if, in operation 220, the local security agent 106 a determines that its current security mode is not blocking security mode.

Regardless of whether the local security agent 106 a allows or denies the request (FIG. 2B, operations 232 or 228), the local security agent 106 a notifies a reconciliation engine 128 on the remote system 112 of the decision, such as by transmitting a communication 126 to the reconciliation engine 128 (FIG. 2B, operation 234). The communication 126 may include any of a variety of information, such as data representing one or more of the following: the identity of the source application 104 a, the destination IP address and port, and the decision made by the local security agent 106 a (e.g., allow or deny). The reconciliation engine 128 may receive and store the communication 126 in any of the ways disclosed herein in connection with the receipt and storage of the communication 114 by the policy management engine 110.

The local security agent 106 a may or may not wait to receive a response from the reconciliation engine 128 before proceeding, depending on the local security agent 106 a's current security mode. More specifically, the local security agent 106 a determines whether it previously denied the connection request 130 in operation 228 or allowed the connection request 130 in operation 232 (FIG. 2B, operation 236). If the connection request 130 was denied, not allowed, the local security agent does not take any further action.

If, instead, the connection request was allowed and was accepted by the destination system 102 b, then the local security agent 106 a determines whether it is currently operating in pessimistic security mode (FIG. 2B, operation 238). If the local security agent 106 a is currently operating in pessimistic security mode, then the local security agent 106 a waits to receive a response from the reconciliation engine 128 (FIG. 2B, operation 240). If the local security agent 106 a does not receive a response within some predetermined timeout period or receives a response indicating the connection does not reconcile with current policies (FIG. 2B, operation 244), then the local security agent 106 a terminates the connection (FIG. 2B, operation 246). If the local security agent 106 a receives a response that confirms the connection reconciles with current policy, the local security agent 106 a leaves the connection active by not taking any action.

If the local security agent 106 a is not currently operating in pessimistic security mode (FIG. 2B, operation 238), then, if the response received by the local security agent 106 a from the reconciliation engine 128 denies the request, then the local security agent 106 a terminates the connection (FIG. 2B, operation 246). If, in operation 242, the reconciliation engine 128 allows the request, the local security agent 106 a leaves the connection active by not taking any action.

Referring now to FIG. 2C, a flowchart is shown of a method 200 c that is performed by the destination local security agent 106 b in one embodiment of the present invention to process the incoming connection request 130 from the source application 104 a. Note that although the method 200 c of FIG. 2C is illustrated as being performed after the method 200 b performed by the source local security agent 106 a in FIG. 2A, this is merely an example and not a requirement of the present invention. For example, the method 200 c of FIG. 2C may begin before the method 200 b of FIG. 2B has completed. As a particular example, the method 200 c of FIG. 2C may begin after the source local security agent 106 a transmits the connection request 130 to the destination system 102 b, and before the remainder of the method 200 b completes.

The destination local security agent 106 b intercepts the inbound connection request 130 transmitted by the source local security agent 106 a, and blocks the request from proceeding further at least until the destination local security agent 106 b has evaluated whether the request 130 matches a local policy (FIG. 2C, operation 248). The local security agent 10 ba identifies, based on the request, the application 104 b that is the destination of the request (FIG. 2C, operation 250). The local security agent 106 b evaluates the request 130 against the locally stored policies 124 b in order to determine whether to allow or deny the request 130 based on any one or more of the following, in any combination: the identity of the destination application 104 b, the IP address and port of the source application 104 a, some or all of the contents of the request 130, and the local policy data 124 b (FIG. 2C, operation 252).

The local security agent 106 b determines, based on its evaluation, whether one of the local policies 124 b covers the communication request 130 (FIG. 2C, operation 254). If one of the local policies 124 b does cover the request, then the local security agent 106 b determines whether the covering policy allows or denies the request (FIG. 2C, operation 256). If the covering policy allows the request, then the local security agent 106 b determines whether the covering policy is current (FIG. 2C, operation 258). The local security agent 106 b may determine whether the covering policy is current in any of a variety of ways. For example, in certain embodiments, the policy management engine 110 may inform the local security agent 106 b that particular policies are current or not current. The local security agent 106 b may treat any particular policy as current in response to being informed by the policy management engine 110 that the policy is current, unless and until the policy management engine 110 subsequently informs the local security agent 106 b that the policy is no longer current. As another example, the local security agent 106 b may convert the status of a policy from current to not current after some predetermined amount of time has passed from when the local security agent 106 b previously set the status of the policy to current.

If the covering policy is current, then the local security agent 106 b sets its security mode to optimistic mode (FIG. 2C, operation 266); otherwise, the local security agent 106 b sets its current security mode to pessimistic security mode (FIG. 2C, operation 264). If the covering policy allows the request 130, then the local security agent 106 b allows the request 130 (FIG. 2C, operation 272), regardless of whether the local policy is current.

If, in operation 272 of FIG. 2C, the local security agent 106 a decides to allow the communication request 130, then, in general, the local security agent 106 b allows the communication request 130 to be provided to the destination application. In other words, the local security agent 106 b may unblock the communication request 130 so that it may be received by the destination application 104 b.

If, in operation 254, the local security agent 106 b determines that none of the local policies 124 b covers the request 130, or, in operation 256, the local security agent 106 b determines that the covering policy denies the request 130, then the local security agent 106 b determines whether its current security mode is blocking security mode (FIG. 2C, operation 260). If the local security agent 106 b's current security mode is blocking security mode, then the local security agent 106 b transmits the request 130 to the policy management engine 110 and awaits a response from the policy management engine 110 (FIG. 2C, operation 262). The policy management engine 110 then evaluates the request 130 against the central policies 118 and sends a response to the local security agent 106 b indicating whether the request should be allowed or denied, based on the central policies 118. The local security agent 106 b receives the response 122 from the policy management engine 110 and determines whether the response 122 indicates that the request 130 should be allowed or denied (FIG. 2C, operation 270). If the response 122 from the policy management engine 110 indicates that the request 130 should be allowed, then the local security agent 106 b allows the connection request 130 (FIG. 2C, operation 272); otherwise, the local security agent 106 b denies the connection request 130 (FIG. 2C, operation 268). The local security agent 106 b also denies the connection request 130 (FIG. 2C, operation 268) if, in operation 260, the local security agent 106 b determines that its current security mode is not blocking security mode.

Regardless of whether the local security agent 106 b allows or denies the request 130 (FIG. 2B, operations 272 or 268), the local security agent 106 b notifies the reconciliation engine 128 on the remote system 112 of the decision, such as by transmitting a communication 132 to the reconciliation engine 128 (FIG. 2C, operation 274). The communication 132 may include any of a variety of information, such as data representing one or more of the following: the identity of the destination application 104 b, the source IP address and port, and the decision made by the local security agent 106 b (e.g., allow or deny). The reconciliation engine 128 may receive and store the communication 132 in any of the ways disclosed herein in connection with the receipt and storage of the communication 114 by the policy management engine 110.

The local security agent 106 b may or may not wait to receive a response from the reconciliation engine 128 before proceeding, depending on the local security agent 106 b's current security mode. More specifically, the local security agent 106 b determines whether it previously denied the connection request 130 in operation 268 or allowed the connection request 130 in operation 272 (FIG. 2C, operation 276). If the connection request 130 was denied, not allowed, the local security agent does not take any further action and the destination application 104 b does not receive the request.

If, instead, the connection request was allowed and was accepted by the destination application 104 b, then the local security agent 106 b determines whether it is currently operating in pessimistic security mode (FIG. 2C, operation 278). If the local security agent 106 b is currently operating in pessimistic security mode, then the local security agent 106 b waits to receive a response from the reconciliation engine 128 (FIG. 2C, operation 270). If the local security agent 106 b does not receive a response within some predetermined timeout period or receives a response indicating the connection does not reconcile with current policies (FIG. 2C, operation 274), then the local security agent 106 b terminates the connection (FIG. 2C, operation 266). If the local security agent 106 b receives a response that confirms the connection reconciles with current policy, the local security agent 106 b leaves the connection active by not taking any action.

If the local security agent 106 b is not currently operating in pessimistic security mode (FIG. 2C, operation 278), then, if the response 136 received by the local security agent 106 b from the reconciliation engine 128 denies the request, then the local security agent 106 b terminates the connection (FIG. 2C, operation 286). If, in operation 282, the reconciliation engine 128 allows the request, the local security agent 106 b leaves the connection active by not taking any action.

As described above, the source and destination local security agents 106 a-b notify the reconciliation engine 128 of their decisions regarding the connection request, in operation 234 of FIG. 2B and operation 274 of FIG. 2C, respectively. The reconciliation engine 128, in response to receiving the communication 126 from the source local security agent 106 a and the communication 132 from the destination local security agent 106 b, collates the data from the two communications 126 and 132 and determines, based on the collated data, whether the collated data indicates that the communication matches any of the policies 118. The reconciliation engine 128 then notifies both the source local security agent 106 a and the destination local security agent 106 b of its decision, via communications 134 and 136, respectively. The ways in which the source and destination local security agents 106 a-b process the communications 134 and 136 are described above in connection with operations 240/242 and 280/282 of FIGS. 2B and 2C, respectively.

The net effect of the method 200 shown in FIGS. 2A-2C is that:

-   -   the source local security agent 106 a makes an informed decision         about whether to allow or deny the connection request based on         the information available to it at the time;     -   if the connection is allowed, the destination local security         agent 106 b makes an informed decision about whether to allow or         deny the request based on the information available at the time;     -   if both the source and destination local security agents 106 a-b         allow the communication request, then the reconciliation engine         128 attempts to confirm the decisions of the source and         destination local security agents 106 a and may either reaffirm         those decisions or override them.

A specific example of an application of the system 100 of FIG. 1 and the methods 200 a-c of FIGS. 2A-2C will now be described. Assume that the source application 104 a is an application named “WebApp” and that the source system 102 a has the IP address 192.168.1.1. Further assume that the destination application 104 b is an application named “Database” and that the destination system 102 b has the IP address 192.168.1.2, and that the “Database” is listening on port 3306. Further assume that the policies 118 include a policy which indicates that the “Database” application is permitted to receive connections from “WebApp” source applications.

The local security agent 106 a reports to the policy management engine that it is running application “WebApp” and that its system has an IP address of 192.168.1.1 (communication 114). The local security agent 106 b reports to the policy management engine 110 that the application “Database” is running and it is listening on IP address 192.168.1.2, port 3306 (communication 116). The policy management engine 110 informs the source local security agent 106 a that application “WebApp” may communicate with 192.168.1.2 over port 3306 (communication 120). The policy management engine 110 informs the destination local security agent 106 b that application “Database” may receive communication from 192.168.1.1 (communication 114).

The “WebApp” application initiates a connection request to IP address 192.168.1.2, port 3306. Because this matches a local policy that was received from the policy management engine 110, the local security agent 106 a uses the techniques disclosed above to allow the connection request 130 to be transmitted to the destination system 102 b and to inform the reconciliation engine that the application named “WebApp” that is executing has initiated a connection request from IP address 192.168.1.1 to IP address 192.168.1.2, port 3306.

On the destination system 102 b, IP address 192.168.1.2 on port 3306 receives an inbound request from IP address 192.168.1.1. Because this matches a local policy that was received from the policy management engine 110, the destination local security agent 106 b uses the techniques disclosed above to receive the connection request 130, to allow the connection request 130 to be provided to the “Database” application, and to informs the reconciliation engine 128 that the application named “Database” that is executing and listening on IP address 192.168.1.2, port 3306, has received a connection request from IP address 192.168.1.1.

The reconciliation engine 128 collates the information it has received from the source and destination local security agents 106 a-b, using any of a variety of data in the received information (e.g., timestamp and/or packet header information). In this example, there are two pieces of information: “‘WebApp’ requested an outbound connection from 192.168.1.1 to 192.168.1.2:3306” and “‘Database’ listening on 192.168.1.2:3306 received an inbound connection request from 192.168.1.1”. The result of this collation is a conclusion by the reconciliation engine 128 that an application named “WebApp” is attempting to make a connection from 192.168.1.1 to an application named “Database” on 192.168.1.2, port 3306. The reconciliation engine 128 determines that this connection request matches the policy which indicates that the “Database” application is permitted to receive connections from “WebApp” applications and, in response to this determination, sends a positive confirmation back to the source local security agent 106 a and the destination local security agent 106 b, indicating that the requested connection satisfies the policies 118. In response to receiving these confirmations, the source and destination local security agents 106 a-b take no further action.

Although in the embodiment of FIGS. 1 and 2A-2B, the reconciliation engine 128 notifies both the source local security agent 106 a and the destination local security agent 106 b, via the communications 134 and 136, of the reconciliation engine 128's policy decision in relation to the request 130, alternatively the reconciliation engine 128 may only notify one of the local security agents 106 a and 106 b. For example, if the reconciliation engine 128 notifies the source local security agent 106 a that the request 130 violates one of the policies 118 either before or after the request 130 has been transmitted to the destination application 104 b on the destination system 102 b, then the source local security agent 106 a may, in response to such a notification, either not provide the request 130 to, or terminate the connection if already established with, the destination system 102 b. As a result, it would not be necessary for the reconciliation engine 128 to notify the destination local security agent 106 b of the policy violation in order to prevent a connection from being established between the source application 104 a and the destination application 104 b.

Similarly, if the reconciliation engine 128 notifies the destination local security agent 106 b that the request 130 violates one of the policies 118, even after the source local security agent 106 a has transmitted the request 130 to the destination system 102 b, then the destination local security agent 106 b may, in response to such a notification, either deny the request 130 and not provide the request 130 to the destination application 104 b, or terminate the connection if it has already been allowed. As a result, it would not be necessary for the reconciliation engine 128 to notify the source local security agent 106 a of the policy violation in order to prevent a connection from being established between the source application 104 a and the destination application 104 b.

Furthermore, although both the source system 102 a and the destination system 102 b in FIG. 1 have their own local security agents 106 a and 106 b, respectively, this is merely an example and does not constitute a limitation of the present invention. Alternatively, for example, only one of the two systems 102 a and 102 b may have a local security agent. As particular examples, the source system 102 a may have its local security agent 106 a, while the destination system 102 b may omit the local security agent 106 b. Conversely, the destination system 102 b may have its local security agent 106 b, while the source system 102 a may omit its local security agent 106 a. Although in these embodiments only one of the two systems 102 a and 102 b, and the reconciliation engine 128, may validate the communication request against the central policies 118 and one of the local policies 124 a and 124 b, such embodiments still provide the benefit of some validation, even if less than in the full system 100 employing three-part validation shown in FIG. 1.

Although the policy management engine 110 is shown in FIG. 1 as being separate and remote from the source system 102 a and the destination system 102 b, this is merely an example and not a limitation of the present invention. More generally, the policy management engine 110 may be implemented in any one or more of the following ways, in any combination:

-   -   as a single component, located remotely from and         network-accessible to, the source system 102 a and destination         system 102 b, as shown in FIG. 1;     -   as a plurality of components which are partially or entirely         redundant, located remotely from and network-accessible to, the         source system 102 a and destination system 102 b;     -   as a single component located within one of the source and         destination systems 102 a and 102 b, respectively, and         network-accessible to the other systems; and     -   as a plurality of components which are partially or entirely         redundant and location within one or more of the source and         destination systems 102 a and 102 b, and optionally         network-accessible to the other systems.

Similarly, although the reconciliation engine 128 is shown in FIG. 1 as being separate and remote from the source system 102 a and the destination system 102 b, this is merely an example and not a limitation of the present invention. More generally, the reconciliation engine 128 may be implemented in any of the ways described above in connection with the policy management engine 110.

Although the local security agents 106 a and 106 b are shown in FIG. 1 as being contained solely within the respective source and destination systems 102 a and 102 b, this is merely an example and not a limitation of the present invention. Each of the local security agents 106 a and 106 b may perform three functions: (1) gathering information about applications executing on the same system (e.g., applications 104 a and 104 b) and the listening ports against which these applications may be bound; (2) gathering information about the network addresses available on the same system, and (3) enforcing the local policies 124 a and 124 b. Any of the local security agents 106 a and 106 b in the systems 102 a and 102 b may perform any, but not all of these functions, in which case the function not performed locally by the local security agent may be performed remotely by another component not contained within the same system as the local security agent. As one particular example, the local security agent 106 a in the source system 102 a may perform the functions of gathering information about applications executing on the source system 102 a (e.g., source application 104 a) and the network addresses available on the source system, but not perform the function of executing local policies 124 a, which may be performed by another component (such as a firewall configured to perform the policy enforcement functions disclosed herein) that is not in the source system 102 a. As yet another example, all of the functions of gathering application and network address information and policy enforcement may be performed remotely from the system (e.g., systems 102 a and 102 b) to which those functions are applied.

The description herein refers to blocking or not allowing network connections to be created, and to terminating existing network connections, in response to determining that a policy would be or has been violated. Such blocking/terminating may be applied to: (1) the specific connection that would violate or has violated a policy; (2) all connections that originate from the same source as a connection that would violate or has violated a policy, and which exist or have been requested at the time the policy violation has been detected; (3) all connections that originate from the same source as a connection that would violate or has violated a policy, including both connections that exist or have been requested at the time the policy violation has been detected, and connections requested in the future (possibly until some time limit has been reached or some other condition has been satisfied); and (4) throttling connections originating from the same source as the connection that has been determined to violate the policy.

Although certain embodiments have been described herein as being applied to a request to establish a network connection (such as the request 130), this is merely an example and not a limitation of the present invention. Alternatively or additionally, embodiments of the present invention may apply the techniques disclosed herein to all content (e.g., every packet) communicated within an existing connection, or to selected content (e.g., periodically sampled packets) within an existing connection.

Referring to FIG. 3, a dataflow diagram is shown of a system 300 for performing symmetrical validation of communication between applications over a network. Referring to FIG. 4A, a flowchart is shown of a method 400 a performed by a policy management engine 310 according to one embodiment of the present invention.

The system 100 includes a source system 302 a and a destination system 302 b. The source system 302 a of FIG. 3 may have any of the properties disclosed herein in connection with the source system 102 a of FIG. 1. Similarly, the destination system 302 b of FIG. 3 may have any of the characteristics disclosed herein in connection with the destination system 102 a of FIG. 3.

The source system 302 a includes a source application 304 a (which may, for example, be installed and executing on the source system 302 a) and the destination system 302 b includes a destination application 304 b (which may, for example, be installed and executing on the destination system 302 b). The source application 304 a of FIG. 3 may have any of the characteristics disclosed herein in connection with the source application 104 a of FIG. 1. Similarly, the destination application 304 b of FIG. 3 may have any of the characteristics disclosed herein in connection with the destination application 104 b of FIG. 1.

An embodiment will now be described for enforcing security policies on a communication that the source system 302 a attempts to initiate with the destination system 302 b. In this embodiment, the source system 302 a includes a local security agent 306 a (which may have any of the characteristics of the local security agent 106 a of FIG. 1) and the destination system 302 b includes a local security agent 306 b (which may have any of the characteristics of the local security agent 106 b of FIG. 1).

The system 300 also includes a policy management engine 310, which may have any of the characteristics of the policy management engine 110 of FIG. 1. Some or all of the local security agents 306 a-b may report the state of the local applications as well as the state of the network on their system to the policy management engine 310 (FIG. 4A, operation 402), such as in any of the ways disclosed herein in connection with operation 202 of FIG. 2A.

Similarly, the local security agent 306 b on the destination system 302 b may obtain and transmit state information for the destination application 304 b (and for any other applications executing on the destination system 302 b) and for the network configuration information of destination system 103 b and transmit such information via communication 316 to the policy management engine 310 in any of the ways disclosed above in connection with the local security agent 306 a, the source system 302 a, the source application 304 a, and the communication 314.

The policy management engine 310 may receive the transmitted state information 314 and 316 and store some or all of it in any suitable form (FIG. 4A, operation 404), such as in any of the ways disclosed herein in connection with operation 204 of FIG. 2A.

The policy management engine 310 may include or otherwise have access to a set of policies 318, which may be stored in the remote system 312. In general, each of the policies 318 specifies both a source application and a destination application, and indicates that the source application is authorized (or not authorized) to communicate with the destination application. The policies 318 may have any of the characteristics disclosed herein in connection with the policies 118 of FIG. 1.

The policy management engine 310 provides, to one or more systems in the system 300 (e.g., the source system 302 a and destination system 302 b), policy data, obtained and/or derived from the policies, representing some or all of the policies that are relevant to the system to which the policy data is transmitted, which may include translating applications into IP address/port combinations (FIG. 4A, operation 406), such as in any of the ways disclosed herein in connection with operation 206 of FIG. 2A.

Like the system 100 of FIG. 1, the system 300 of FIG. 3 may operate in an Optimistic, Pessimistic, or Blocking security modes, which are described in more detail above.

The policy management engine 310 creates a trusted public key certificate 340 (such as an X.509 root certificate) (FIG. 4A, operation 408). The policy management engine 310 distributes (via communications 342 and 344) copies of the certificate 340 to the agents 306 a and 306 b, respectively (FIG. 4A, operation 410). The agents 306 a and 306 b store their copies of the certificate 340 as certificate copies 356 a and 356 b, respectively (FIG. 4A, operation 412).

Although X.509 is provided above as an example of a public key certificate infrastructure, this is merely an example and not a limitation of the present invention. Other public key certificate infrastructures may be used. One benefit of X.509 is that it allows a host or website to create a document that proves the ownership of a public key. It used public-key encryption to guarantee that the document is valid. In addition to identity, the certificate may include other information. As described below, embodiments of the present invention may use the information in the X.509 certificate to create a “web of trust” among the agents 106 a-b, so that they can trust the information they have received from a (putative) other agent and act on it.

Referring now to FIG. 4B, a flowchart is shown of a method 400 b that is performed by the source local security agent 306 a in one embodiment of the present invention to process an outgoing connection request. Note that although the method 400 b of FIG. 4B may be performed following the method 400 a performed by the policy management agent 310 in FIG. 4A, this is merely an example and not a requirement of the present invention. Rather, the method 400 b of FIG. 4B (and the method 400 c of FIG. 4C) may operate independently of the method 400 a of FIG. 4A.

Now consider an example in which the source application 304 a makes a network request to communicate with the destination application 304 b. Although this particular example will be described in connection with this particular request, the techniques disclosed herein may be applied more generally to any request made by any application to communication with any other application.

The local security agent that is on the same system as the requesting application, which in this example is the local security agent 306 a that is on the same system 302 a as the requesting application 304 a, detects that the requesting application 304 a has made the communication request, intercepts the request, and blocks the request from proceeding further at least until the source local security agent 306 a has evaluated whether the request matches a local policy (FIG. 4B, operation 414). The local security agent 306 a identifies, based on the request, the application 304 a that is the source of the request (FIG. 4B, operation 416).

Recall that the local security agents 306 a-b have already received and stored intermediate signing certificates 356 a-b, respectively, from the policy management engine 310. The policy management engine 310 is a source that is trusted a priori by both of the local security agents 306 a-b. Furthermore, the intermediate certificates 356 a-b are derived from common root certificate 340, which is known only to the policy management engine 310.

After the source local security agent 306 a intercepts the outgoing communication request, the source local security agent 306 a creates its own local certificate 358 a, referred to herein as a “client certificate,” based on the local intermediate certificate 356 a (FIG. 4B, operation 418). In general, the client certificate 358 a extends the certificate chain and trustworthiness of the intermediate certificate 356 a. For example, the local security agent 306 a may create the client certificate 358 a based on the intermediate certificate 356 a by adding, to the intermediate certificate 356 a: (1) identifying metadata of the source system 302 a on which the local security agent 306 a resides; and (2) application fingerprint information for the source application 304 a.

Similarly, the destination local security agent 306 b creates its own local client certificate 358 b based on the local intermediate certificate 356 b (FIG. 4B, operation 420). In general, the client certificate 358 b extends the certificate chain and trustworthiness of the intermediate certificate 356 b. For example, the local security agent 306 b may create the client certificate 358 b based on the intermediate certificate 356 b by adding, to the intermediate certificate 356 b: (1) identifying metadata of the destination system 302 b on which the local security agent 306 b resides; and (2) application fingerprint information for the destination application 304 b.

The local security agents 306 a-b then exchange their respective client certificates 358 a-b, such as by using the mTLS protocol (FIG. 4B, operation 422).

The client certificates 358 a-b are based on the root certificate 340. The root certificate 340 has already been signed by the policy management engine 310, and also received by the security agents 306 a-b, and this ends the involvement of the policy management engine 310. Because the root certificate 340 includes a cryptographic signature, proving it originates from the backend (e.g., the policy management engine 310), the client certificates 358 a-b, which extend the root certificate 340, are also trusted just as the root certificate 340 is trusted. When the client certificates 358 a-b are exchanged, the receiver of the client certificate can trust that the sender possesses a root certificate and hence that the information it sends may be trusted.

Both of the local security agents 306 a-b then have the information required to decide whether their local policies 324 a-b, respectively, will allow (or refuse) the communication request from the source application 304 a, without the involvement of the remote system 312. Specific examples of techniques for making the allow/refuse decision will now be described.

The local security agent 306 a evaluates the request against the locally stored policies 324 a in order to determine whether to allow or deny the request based on any one or more of the following, in any combination: the identity of the source application 304 a, the IP address and port of the destination application 304 b, some or all of the contents of the request, and the local policy data 324 a (FIG. 4B, operation 424).

The local security agent 306 a determines, based on its evaluation, whether one of the local policies 324 a covers the communication request (FIG. 4B, operation 426). If one of the local policies 324 a does cover the request, then the local security agent 306 a determines whether the covering policy allows or denies the request (FIG. 4B, operation 428). If the covering policy allows the request, then the local security agent 306 a determines whether the covering policy is current, such as in any of the ways disclosed above in connection with FIG. 2B (FIG. 4B, operation 430).

If the covering policy is current, then the local security agent 306 a sets its security mode to optimistic mode (FIG. 4B, operation 432); otherwise, the local security agent 306 a sets its current security mode to pessimistic security mode (FIG. 4B, operation 434). If the covering policy allows the request, then the local security agent 306 a allows the request (FIG. 4B, operation 436), regardless of whether the local policy is current.

If, in operation 428 of FIG. 4B, the local security agent 306 a decides to allow the communication request, then, in general, the local security agent 306 a allows the communication request to be transmitted to the destination application 304 b. Such transmission may occur using traditional techniques. In other words, the local security agent 306 a may unblock the communication request and permit it to be transmitted normally.

If, in operation 426, the local security agent 306 a determines that none of the local policies 324 a covers the request, or, in operation 428, the local security agent 306 a determines that the covering policy denies the request, then the local security agent 306 a determines whether its current security mode is blocking security mode (FIG. 4B, operation 438). Furthermore, note that the local policies 324 a may include a policy which specifically indicates the action to be performed if none of the local policies 324 a covers the request. If the local policies 324 a include such a policy, then the local security agent 306 a may perform the action specified by that policy if the local security agent 306 a determines that none of the local policies 324 a covers the request.

If the local security agent 306 a's current security mode is blocking security mode, then the local security agent 306 a waits until both the client certification exchange is completed and until the information from the certificate has been used to check with respect to the relevant set of policies whether to allow or deny the communication (FIG. 4B, operation 442). If the local security agent 306 a determines that the request should be allowed, then the local security agent 306 a allows the connection request (FIG. 4B, operation 436); otherwise, the local security agent 106 a denies the connection request (FIG. 4B, operation 444). The local security agent 306 a also denies the connection request (FIG. 4B, operation 444) if, in operation 438, the local security agent 306 a determines that its current security mode is not blocking security mode.

Referring now to FIG. 4C, a flowchart is shown of a method 400 c that is performed by the destination local security agent 306 b in one embodiment of the present invention to process the incoming connection request 330 from the source application 304 a. Note that although the method 400 c of FIG. 4C is illustrated as being performed after the method 400 b performed by the source local security agent 306 a in FIG. 4A, this is merely an example and not a requirement of the present invention. For example, the method 400 c of FIG. 4C may begin before the method 400 b of FIG. 4B has completed. As a particular example, the method 400 c of FIG. 4C may begin after the source local security agent 306 a transmits the connection request 330 to the destination system 302 b, and before the remainder of the method 400 b completes.

The destination local security agent 306 b intercepts the inbound connection request 330 transmitted by the source local security agent 306 a, and blocks the request 330 from proceeding further at least until the destination local security agent 306 b has evaluated whether the request 330 matches a local policy (FIG. 4C, operation 448). The local security agent 306 b identifies, based on the request, the application 304 b that is the destination of the request (FIG. 4C, operation 450).

The local security agent 306 b evaluates the request 330 against the locally stored policies 324 b in order to determine whether to allow or deny the request 330 based on any one or more of the following, in any combination: the identity of the destination application 304 b, the IP address and port of the source application 304 a, some or all of the contents of the request 330, and the local policy data 324 b (FIG. 4C, operation 452).

The local security agent 306 b determines, based on its evaluation, whether one of the local policies 324 b covers the communication request 330 (FIG. 4C, operation 454). If one of the local policies 324 b does cover the request, then the local security agent 306 b determines whether the covering policy allows or denies the request (FIG. 4C, operation 456). If the covering policy allows the request, then the local security agent 306 b determines whether the covering policy is current, such as in any of the ways disclosed herein in connection with FIG. 2C (FIG. 4C, operation 458).

If the covering policy is current, then the local security agent 306 b sets its security mode to optimistic mode (FIG. 4C, operation 466); otherwise, the local security agent 306 b sets its current security mode to pessimistic security mode (FIG. 4C, operation 464). If the covering policy allows the request 330, then the local security agent 306 b allows the request 330 (FIG. 4C, operation 472), regardless of whether the local policy is current.

If, in operation 472 of FIG. 4C, the local security agent 306 a decides to allow the communication request 330, then, in general, the local security agent 306 b allows the communication request 330 to be provided to the destination application. In other words, the local security agent 306 b may unblock the communication request 330 so that it may be received by the destination application 304 b.

If, in operation 454, the local security agent 306 b determines that none of the local policies 324 b covers the request 330, or, in operation 456, the local security agent 306 b determines that the covering policy denies the request 330, then the local security agent 306 b determines whether its current security mode is blocking security mode (FIG. 4C, operation 460). Furthermore, note that the local policies 324 b may include a policy which specifically indicates the action to be performed if none of the local policies 324 b covers the request. If the local policies 324 b include such a policy, then the local security agent 306 b may perform the action specified by that policy if the local security agent 306 b determines that none of the local policies 324 b covers the request.

If the local security agent 306 b's current security mode is blocking security mode, then the local security agent 306 b waits until both the client certification exchange is completed and until the information from the certificate has been used to check with respect to the relevant set of policies whether to allow or deny the communication (FIG. 4C, operation 462). If the local security agent 306 b determines that the request should be allowed, then the local security agent 306 b allows the connection request 330 (FIG. 4C, operation 272); otherwise, the local security agent 306 a denies the connection request 330 (FIG. 4C, operation 468). The local security agent 306 b also denies the connection request 330 (FIG. 4C, operation 468) if, in operation 460, the local security agent 306 b determines that its current security mode is not blocking mode.

The net effect of the method 400 shown in FIGS. 4A-4C is that:

-   -   the source local security agent 306 a makes an informed decision         about whether to allow or deny the connection request based on         the information available to it at the time; and     -   if the connection is allowed, the destination local security         agent 306 b makes an informed decision about whether to allow or         deny the request based on the information available at the time.

One of the advantages of embodiments of the invention shown in FIGS. 3 and 4A-4C is that they may be used to enable the network policies 318 to be enforced in a distributed manner by the local security agents 306 a-b, without the use of a centralized backend, such as the remote system 312.

One of the advantages of embodiments of the present invention is that they may be used to protect against policy violations without requiring alterations to the source application 104 a, the destination application 104 b, or the network traffic between them (e.g., the communication request 130). This ability simplifies the installation, configuration, and maintenance of the system 100 greatly in comparison to systems which require applications and/or network traffic to be modified in order to detect policy violations.

Another advantage of embodiments of the present invention is that they have visibility into the network-related information of both the source and destination sides of a network communication, thereby enabling network security policies to be validated based on such information from both sides. This provides significant advantages over prior art systems, which use only information from the source or the destination, and which therefore lack, for example, information about the identity of the application executing on the other side of the communication. Access to information from both sides of network communications enables embodiments of the present invention to identify and prevent violations of network security policies which cannot be identified accurately using prior art techniques that rely solely on information from one side of the communication.

It is to be understood that although the invention has been described above in terms of particular embodiments, the foregoing embodiments are provided as illustrative only, and do not limit or define the scope of the invention. Various other embodiments, including but not limited to the following, are also within the scope of the claims. For example, elements and components described herein may be further divided into additional components or joined together to form fewer components for performing the same functions.

Any of the functions disclosed herein may be implemented using means for performing those functions. Such means include, but are not limited to, any of the components disclosed herein, such as the computer-related components described below.

The techniques described above may be implemented, for example, in hardware, one or more computer programs tangibly stored on one or more computer-readable media, firmware, or any combination thereof. The techniques described above may be implemented in one or more computer programs executing on (or executable by) a programmable computer including any combination of any number of the following: a processor, a storage medium readable and/or writable by the processor (including, for example, volatile and non-volatile memory and/or storage elements), an input device, and an output device. Program code may be applied to input entered using the input device to perform the functions described and to generate output using the output device.

Embodiments of the present invention include features which are only possible and/or feasible to implement with the use of one or more computers, computer processors, and/or other elements of a computer system. Such features are either impossible or impractical to implement mentally and/or manually. For example, embodiments of the present invention intercept and then may block network connection requests. Such features are applicable only within the context of networked communications and cannot be performed mentally and/or manually.

Any claims herein which affirmatively require a computer, a processor, a memory, or similar computer-related elements, are intended to require such elements, and should not be interpreted as if such elements are not present in or required by such claims. Such claims are not intended, and should not be interpreted, to cover methods and/or systems which lack the recited computer-related elements. For example, any method claim herein which recites that the claimed method is performed by a computer, a processor, a memory, and/or similar computer-related element, is intended to, and should only be interpreted to, encompass methods which are performed by the recited computer-related element(s). Such a method claim should not be interpreted, for example, to encompass a method that is performed mentally or by hand (e.g., using pencil and paper). Similarly, any product claim herein which recites that the claimed product includes a computer, a processor, a memory, and/or similar computer-related element, is intended to, and should only be interpreted to, encompass products which include the recited computer-related element(s). Such a product claim should not be interpreted, for example, to encompass a product that does not include the recited computer-related element(s).

Each computer program within the scope of the claims below may be implemented in any programming language, such as assembly language, machine language, a high-level procedural programming language, or an object-oriented programming language. The programming language may, for example, be a compiled or interpreted programming language.

Each such computer program may be implemented in a computer program product tangibly embodied in a machine-readable storage device for execution by a computer processor. Method steps of the invention may be performed by one or more computer processors executing a program tangibly embodied on a computer-readable medium to perform functions of the invention by operating on input and generating output. Suitable processors include, by way of example, both general and special purpose microprocessors. Generally, the processor receives (reads) instructions and data from a memory (such as a read-only memory and/or a random access memory) and writes (stores) instructions and data to the memory. Storage devices suitable for tangibly embodying computer program instructions and data include, for example, all forms of non-volatile memory, such as semiconductor memory devices, including EPROM, EEPROM, and flash memory devices; magnetic disks such as internal hard disks and removable disks; magneto-optical disks; and CD-ROMs. Any of the foregoing may be supplemented by, or incorporated in, specially-designed ASICs (application-specific integrated circuits) or FPGAs (Field-Programmable Gate Arrays). A computer can generally also receive (read) programs and data from, and write (store) programs and data to, a non-transitory computer-readable storage medium such as an internal disk (not shown) or a removable disk. These elements will also be found in a conventional desktop or workstation computer as well as other computers suitable for executing computer programs implementing the methods described herein, which may be used in conjunction with any digital print engine or marking engine, display monitor, or other raster output device capable of producing color or gray scale pixels on paper, film, display screen, or other output medium.

Any data disclosed herein may be implemented, for example, in one or more data structures tangibly stored on a non-transitory computer-readable medium. Embodiments of the invention may store such data in such data structure(s) and read such data from such data structure(s). 

1. A method performed by at least one computer processor executing computer program instructions stored on at least one non-transitory computer-readable medium, the method comprising: (A) at a source local security agent on a source computer system comprising at least one first microprocessor, transmitting the state of an application executing on the source computer system and a first state of a network to a policy management engine; (B) at the policy management engine, receiving the state of the application executing on the source computer system and the first state of the network; (C) at the policy management engine, transmitting a first set of network application security policies to the source local security agent; (D) at the source local security agent, receiving the first set of network application security policies; (E) at the source local security agent, intercepting an outgoing network connection request from the application executing on the source computer system; (F) at the source local security agent, determining whether at least one of the first set of network application security policies covers the outgoing connection request; (G) at a destination local security agent on a destination computer system comprising at least one second microprocessor, transmitting the state of an application executing on the destination computer system and a second state of the network to the policy management engine; (H) at the policy management engine, receiving the state of the application executing on the destination computer system and the second state of the network; (I) at the policy management engine, transmitting a second set of network application security policies to the destination local security agent; (J) at the destination local security agent, receiving the second set of network application security policies; (K) at the destination local security agent, intercepting an incoming network connection request from the application executing on the destination computer system; (L) at the destination local security agent, determining whether at least one of the second set of network application security policies covers the incoming connection request; (M) at a reconciliation engine, determining whether a third set of network application security policies covers the outgoing connection request and the incoming connection request, wherein the third set of network application security policies is a superset of the first set of network application security policies and the second set of network application security policies; and (N) if the reconciliation engine determines that the third set of network application security policies does not cover the outgoing connection request and the incoming connection request, then instructing the source local security agent to terminate a first connection created in response to the outgoing connection request and instructing the destination local security agent to terminate a second connection created in response to the incoming connection request. 